电感耦合等离子体质谱测定食盐中的铅含量

Determination of lead in table salt by using internal standard method and standard addition method of ICP-MS

选用铑(103 Rh)作为内标物质,采用电感耦合等离子体质谱内标法和标准加入法分别对浓度为4%,8%,12%,16%,20%的食盐样品溶液中铅的加标回收率进行测定。试验结果表明:采用内标法测定时,当食盐样品浓度从4%增加至20%时,内标回收率从54.8%降低至5.1%,各浓度梯度高、中、低加标浓度样品的加标回收率在90%~112%;采用标准加入法测定时各浓度食盐样品基体对应的内标回收率基本保持在100%左右,各浓度梯度高、中、低加标浓度样品的加标回收率在91%~114%;采用电感耦合等离子体质谱内标法和标准加入法能够快速、准确地测定不同浓度食盐样品中的铅含量,而且食盐样品基体浓度从4%增加到20%并未对方法的准确性造成影响。

Abstract： Rhodium （^103 Rh） was used as internal standard substance, and the recovery rates of lead in samples with different salt concen- tration of 4%, 8%, 12%, 16% were determined by using internal standard correction method and standard addition method of Induc- tively Coupled Plasma Mass Spectrometry（ICP--MS）. The experi- mental results show that ： When determined by internal standard cor- rection method, as the table salt sample＇s concentration increased from 4% to 20%, the recovery rates of the internal standard reduced from 54.8% to 5.1 %, and the recovery rates of lead in high, medium and low standard addition samples with different concentration gradi- ents of table salt were between 90% ~ 112%; When determined by standard addition method, the internal standard recovery rates of each matrix of different salt concentration remained about 100%, and the recovery rates of lead in high, medium and low standard addition samples with different concentration gradients of table salt were between 91% ~ 1 14%; Both the two analytical methods can accu- rately determine the content of lead in different concentration of table salt samples, and the accuracy of the methods did not affect although the ma- trix of table salt＇s concentration increased from 4% to 20%.